| 摘要 |
PURPOSE:To obtain the variable wavelength filter which can vary pass wavelengths by light signals by admitting the control light having the photon energy larger than the photon energy corresponding to the forbidden band width of a compd. semiconductor constituting an optical guide layer into the optical guide layer thereby changing the resonance wavelength of an active layer. CONSTITUTION:The optical guide layer 12 consisting of the compd. semiconductor having the forbidden band width larger than the forbidden band width corresponding to the photon energy of input light is provided adjacently to the active layer 13. The control light having the photon energy larger than the photon energy corresponding to the forbidden band width of the compd. semiconductor constituting the optical guide layer 12 is admitted into this optical guide layer 12. The refractive index of the optical guide layer 12 is then changed and the resonance wavelength of the Fabry-Perot resonator formed of the cleavage face at the input end of the active layer 13 and the cleavage face of the output end is changed. Only the light of the resonance wavelength of this Fabry-Perot resonator is selected and outputted. The variable wavelength filter which can vary the pass wavelength by the light signals is obtd. in this way. |
